Heat-dissipation fan

ABSTRACT

A heat-dissipation fan includes a first plate, a second plate, a ring wall, a spacing rib, a stator and a fan wheel. The first plate comprises a vent, and an accommodating space can be defined by the first plate, the second plate and the ring wall. The spacing rib is disposed at the accommodating space. A passage is formed between the spacing rib and the ring wall, and an end portion of the spacing rib and the ring wall are spaced apart to form an opening. The passage is in communication with the vent, and the opening is in communication with the passage and the accommodating space. The fan wheel can be driven by the stator, and the dust adhered to the accommodating space may be discharged through the opening, the passage and the vent via airflow generated by rotating fan wheel.

FIELD OF THE INVENTION

The present invention is generally related to a heat-dissipation fan, which particularly relates to the heat-dissipation fan with dust exhaustion function.

BACKGROUND OF THE INVENTION

A conventional heat-dissipation fan 10 as indicated in FIGS. 19 and 20 includes a bottom plate 11, a ring wall 12, a stator 13, a circuit board 14, a fan wheel 15 and a lid 16. The bottom plate 11 comprises a first vent 11 a, the ring wall 12 comprises a second vent 12 a, and the ring wall 12 is disposed at the bottom plate 11 so as to define an accommodating slot 17. The stator 13, the circuit board 14 and the fan wheel 15 are disposed within the accommodating slot 17, wherein the circuit board 14 is electrically connected with the stator 13 to drive the fan wheel 15 into rotation counterclockwise. The lid 16 is coupled to the ring wall 12 and comprises a third vent 16 a. When the fan wheel 15 rotates counterclockwise, the air outside the heat-dissipation fan 10 is exhausted into the accommodating slot 17 through the first vent 11 a and the third vent 16 a, and the air is eventually discharged from the second vent 12 a. However, for the reason that the dust is adhered to the fan wheel 15, the stator 13, the circuit board 14, an inner surface of the ring wall 12, a peripheral of the first vent 11 a and a peripheral of the third vent 16 a, long-term accumulated dusts may lower the rotation speed of the fan wheel 15 therefore lowering effectiveness of heat dissipation. Or, the heat-dissipation fan 10 fails to operate normally.

SUMMARY

A rotating fan wheel of a conventional heat-dissipation fan may gather the dust within the conventional heat-dissipation fan to lead a slower rotation speed of the fan wheel or a destruction of the heat-dissipation fan. The primary object of the present invention is to overcome mentioned issue of the conventional heat-dissipation fan. A heat-dissipation fan in this invention includes a first plate, a second plate, a ring wall, a spacing rib, a stator, a circuit board and a fan wheel. The first plate comprises a first top surface, a first bottom surface, a first aperture and a vent, and a second plate comprises a second top surface, a second bottom surface and a second aperture. The ring wall comprises an inner surface, an outer surface and a first opening, wherein the ring wall is disposed between the first plate and the second plate, and an accommodating space can be defined by the first plate, the second plate and the ring wall. The spacing rib is disposed at the accommodating space. A passage is formed between the spacing rib and the ring wall, the spacing rib comprises a first end portion and a second end portion, wherein the second end portion and the ring wall are spaced apart to form a second opening. The passage is in communication with the vent, and the second opening is in communication with the passage and the accommodating space. The stator is disposed at the accommodating space. The circuit board is electrically connected with the stator and includes a forward/reverse control unit. The fan wheel is coupled to the stator and comprises a hub and a plurality of blades. The rotation direction of the fan wheel is controllable by the forward/reverse control unit. When the fan wheel is rotated in a certain direction, the air inside the accommodating space may be discharged through the second opening, the passage and the vent, which may push forward the dust that is adhered to the accommodating space to be discharged. Therefore, the cleaning of the heat-dissipation fan and dust exhaustion can be achieved simultaneously.

Besides, the first end portion of the spacing rib and the inner surface of the ring wall are spaced apart by a first spacing, the second end portion of the spacing rib and the inner surface of the ring wall are spaced apart by a second spacing, the first spacing has a first width, the second spacing has a second width, and the passage between the spacing rib and the inner surface of the ring wall is tapered from the second width to the first width so that the passage can be regarded as a pressure accumulation passage. When the air inside the accommodating space passes through the second opening and the passage, a pressure difference is generated for increasing the pressure of the air that is penetrated through the vent. A relative large air pressure may prevent the dust from gathering around the vent, and an obstruction of the vent can be avoidable.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective exploded diagram illustrating a heat-dissipation fan in accordance with a first embodiment of the present invention.

FIG. 2 is a partial assembly diagram illustrating a heat-dissipation fan in accordance with a first embodiment of the present invention.

FIG. 3 is an action diagram illustrating a heat-dissipation fan in accordance with a first embodiment of the present invention.

FIG. 4 is an action diagram illustrating a heat-dissipation fan in accordance with a first embodiment of the present invention.

FIG. 5 is a perspective exploded diagram illustrating a heat-dissipation fan in accordance with a second embodiment of the present invention.

FIG. 6 is a partial assembly diagram illustrating a heat-dissipation fan in accordance with a second embodiment of the present invention.

FIG. 7 is a perspective exploded diagram illustrating a heat-dissipation fan in accordance with a third embodiment of the present invention.

FIG. 8 is a partial assembly diagram illustrating a heat-dissipation fan in accordance with a third embodiment of the present invention.

FIG. 9 is an action diagram illustrating a heat-dissipation fan in accordance with a third embodiment of the present invention.

FIG. 10 is a perspective exploded diagram illustrating a heat-dissipation fan in accordance with a fourth embodiment of the present invention.

FIG. 11 is a partial assembly diagram illustrating a heat-dissipation fan in accordance with a fourth embodiment of the present invention.

FIG. 12 is an action diagram illustrating a heat-dissipation fan in accordance with a fourth embodiment of the present invention.

FIG. 13 is a perspective exploded diagram illustrating a heat-dissipation fan in accordance with a fifth embodiment of the present invention.

FIG. 14 is a partial assembly diagram illustrating a heat-dissipation fan in accordance with a fifth embodiment of the present invention.

FIG. 15 is an action diagram illustrating a heat-dissipation fan in accordance with a fifth embodiment of the present invention.

FIG. 16 is an action diagram illustrating a heat-dissipation fan in accordance with a fifth embodiment of the present invention.

FIG. 17 is a perspective exploded diagram illustrating a heat-dissipation fan in accordance with a sixth embodiment of the present invention.

FIG. 18 is an action diagram illustrating a heat-dissipation fan in accordance with a sixth embodiment of the present invention.

FIG. 19 is a perspective exploded diagram of a conventional heat-dissipation fan.

FIG. 20 is a perspective assembly diagram of a conventional heat-dissipation fan.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIGS. 1, 2, 3 and 4, a heat-dissipation fan 100 in accordance with a first preferred embodiment of the present invention includes a first plate 110, a second plate 120, a ring wall 130, a spacing rib 150, a stator 170, a circuit board 180 and a fan wheel 190. The first plate 110 comprises a first top surface 111, a first bottom surface 112, a first aperture 113 and a vent 114, wherein the first aperture 113 and the vent 114 are penetrated through the first top surface 111 and the first bottom surface 112. Referring to FIG. 1, in this embodiment, the first plate 110 further comprises a supporting base 115 disposed at the first aperture 113. The second plate 120 comprises a second top surface 121, a second bottom surface 122, and a second aperture 123 penetrated through the second top surface 121 and the second bottom surface 122. The ring wall 130 comprises an inner surface 131, an outer surface 132 and a first opening 133. With reference to FIG. 2, the ring wall 130 is coupled to the first top surface 111 of the first plate 110, and the ring wall 130 is disposed between the first plate 110 and the second plate 120. The second bottom surface 122 of the second plate 120 is coupled to the ring wall 130 and faces toward the first top surface 111 of the first plate 110, wherein an accommodating space 140 can be defined by the first plate 110, the second plate 120 and the ring wall 130. The spacing rib 150 is located between the first plate 110 and the second plate 120 and is disposed at the accommodating space 140. In this embodiment, a passage 160 is formed between the spacing rib 150 and the ring wall 130. The spacing rib 150 comprises a first end portion 151 and a second end portion 152, wherein the second end portion 152 and the ring wall 130 are spaced apart to form a second opening 161. The passage 160 is in communication with the vent 114, and the second opening 161 is in communication with the passage 160 and the accommodating space 140. The first end portion 151 of the spacing rib 150 is in contact against the inner surface 131 of the ring wall 130. In this embodiment, the first end portion 151 of the spacing rib 150 is formed as one piece with the inner surface 131 of the ring wall 130. With reference to FIGS. 1 and 3, the first end portion 151 of the spacing rib 150 and the inner surface 131 of the ring wall 130 are spaced apart by a first spacing 162, the second end portion 152 of the spacing rib 150 and the inner surface 131 of the ring wall 130 are spaced apart by a second spacing 163, in this embodiment, the second spacing 163 is larger than the first spacing 162. The first spacing 162 has a first width, and the second spacing 163 has a second width. The passage 160 between the spacing rib 150 and the inner surface 131 of the ring wall 130 is tapered from the second width to the first width so that the passage 160 can be regarded as a pressure accumulation passage. The spacing rib 150 can be an arc-shaped plate. The stator 170 is disposed at the accommodating space 140, and the stator 170 is located between the first plate 110 and the second plate 120. Besides, the stator 170 and the circuit board 180 are coupled to the supporting base 115 of the first plate 110, wherein the circuit board 180 includes a forward/reverse control unit 181, and the forward/reverse control unit 181 can be a micro controller unit or an analog circuit. The forward/reverse control unit 181 is electrically connected with the circuit board 180, and the circuit board 180 is electrically connected with the stator 170. The fan wheel 190 is coupled to the stator 170 and can be driven to rotate by the stator 170. The fan wheel 190 comprises a hub 191 and a plurality of blades 192. The rotation direction of the fan wheel 190 is controllable by the forward/reverse control unit 181. Therefore, the fan wheel 190 can be driven to rotate in a first direction or in a second direction opposite to the first direction, wherein the first direction can be clockwise or counterclockwise. In this embodiment, the first direction is clockwise, and the second direction is counterclockwise.

With reference to FIGS. 1, 2 and 3, when the fan wheel 190 is rotated in the second direction controlled by the forward/reverse control unit 181, the rotating blades 192 of the fan wheel 190 enable the air inside the accommodating space 140 to generate airflow A1. The air outside the heat-dissipation fan 100 may pass through the first aperture 113 of the first plate 110 and the second aperture 123 of the second plate 120, and the air is eventually exhausted into the accommodating space 140 via airflow A1. In the mean time, the air inside the accommodating space 140 may be discharged from the first opening 133 of the ring wall 130 via airflow A1 therefore forming a gas circulation to achieve heat dissipation function.

With reference to FIGS. 1, 2 and 4, when the fan wheel 190 is rotated in the first direction controlled by the forward/reverse control unit 181, the rotating blades 192 of the fan wheel 190 enable the air within the accommodating space 140 to generate airflow A2. The air outside the heat-dissipation fan 100 may pass through the first opening 133 of the ring wall 130 and is exhausted into the accommodating space 140 via airflow A2. In the mean time, the air inside the accommodating space 140 may be discharged through the second opening 161, the passage 160 and the vent 114 via airflow A2, which may push forward the dust adhered to the accommodating space 140 to be discharged from the vent 114 of the heat-dissipation fan 100 as well. Accordingly, the cleaning of the heat-dissipation fan 100 and dust exhaustion can be achieved simultaneously.

With reference to FIG. 4 again, for the reason that the passage 160 between the spacing rib 150 and the inner surface 131 of the ring wall 130 is tapered from the second width to the first width so that the passage 160 can be regarded as a pressure accumulation passage. Under the same airflow pressure, when the air within the accommodating space 140 passes through the second opening 161 and the passage 160, a pressure difference is generated for increasing the pressure of the air that is penetrated through the vent 114. A relative large air pressure may prevent the dust from gathering around the vent 114, and an obstruction of the vent 114 can be avoidable. It is beneficial for exhausting the dust of the heat-dissipation fan 100.

A second embodiment of this invention can be referred to FIGS. 5 and 6. The difference between the second embodiment and the first embodiment is that a vent 124 is disposed at the second plate 120, and the vent 124 is penetrated through the second top surface 121 and the second bottom surface 122. When the fan wheel 190 is rotated in the first direction controlled by the forward/reverse control unit 181, the dust within the accommodating space 140 may be discharged through the second opening 161, the passage 160 and the vent 124. Accordingly, the cleaning of the heat-dissipation fan 100 and dust exhaustion can be achieved simultaneously.

A third embodiment of this invention can be referred to FIGS. 7-9, the difference between the third embodiment and the first embodiment is that the spacing rib 150 is formed as one piece with the first top surface 111 of the first plate 110. Referring to FIGS. 7, 8 and 9 again, the ring wall 130 is coupled to the first top surface 111 of the first plate 110, the second plate 120 is coupled to the ring wall 130, and the passage 160 is formed between the spacing rib 150 and the ring wall 130. In this embodiment, the first end portion 151 of the spacing rib 150 is in contact against the inner surface 131 of the ring wall 130. With reference to FIG. 9, when the fan wheel 190 is rotated in the first direction controlled by the forward/reverse control unit 181, the air inside the accommodating space 140 may be discharged through the second opening 161, the passage 160 and the vent 114 via airflow A2, which may push forward the dust adhered to the accommodating space 140 to be discharged from the heat-dissipation fan 100 as well. Accordingly, the cleaning of the heat-dissipation fan 100 and dust exhaustion can be achieved simultaneously.

A fourth embodiment of this invention can be referred to FIGS. 10, 11 and 12. The difference between the fourth embodiment and the first embodiment is that the spacing rib 150 is formed as one piece with the second bottom surface 122 of the second plate 120. Referring to FIGS. 10, 11 and 12 again, the ring wall 130 is coupled to the second bottom surface 122 of the second plate 120, and the passage 160 is formed between the spacing rib 150 and the ring wall 130. In this embodiment, the first end portion 151 of the spacing rib 150 is in contact against the inner surface 131 of the ring wall 130, and the second end portion 152 and the ring wall 130 are spaced apart to form the second opening 161. The passage 160 is in communication with the vent 114 of the first plate 110. With reference to FIG. 12, when the fan wheel 190 is rotated in the first direction controlled by the forward/reverse control unit 181, the air inside the accommodating space 140 may be discharged through the second opening 161, the passage 160 and the vent 114 via airflow A2, which may push forward the dust adhered to the accommodating space 140 to be discharged from the heat-dissipation fan 100 as well. Accordingly, the cleaning of the heat-dissipation fan 100 and dust exhaustion can be achieved simultaneously.

A fifth embodiment of this invention can be referred to FIGS. 13-16. The difference between the fifth embodiment and the first embodiment is that the heat-dissipation fan 100 further includes an active spacing rib 150 a disposed at the second opening 161. Referring to FIGS. 13 and 14, the active spacing rib 150 a comprises a pivoted portion 150 b and a swing portion 150 c in connection with the pivoted portion 150 b. In this embodiment, the pivoted portion 150 b is pivotally connected with the first top surface 111 of the first plate 110 and the second bottom surface 122 of the second plate 120. The ring wall 130 is coupled to the first top surface 111 of the first plate 110, the second plate 120 is coupled to the ring wall 130, the pivoted portion 150 b is adjacent to the second end portion 152 of the spacing rib 150, and the swing portion 150 c is swingable in the accommodating space 140. In this embodiment, the heat-dissipation fan 100 further includes a resilient member S having a first end S1 and a second end S2, wherein the resilient member S can be chosen from a leaf spring or a conventional spring. With reference to FIGS. 13, 14, 15 and 16, in this embodiment, the resilient member S can be a leaf spring, the first end S1 of the resilient member S is fixed at the spacing rib 150, and the second end S2 is fixed at the active spacing rib 150 a. Preferably, the heat-dissipation fan 100 further includes a pillar P disposed between the active spacing rib 150 a and the blades 192 of the fan wheel 190. In this embodiment, the pillar P is formed as one piece with the first top surface 111 of the first plate 110. Or, in another embodiment, the pillar P is formed as one piece with the second bottom surface 122 of the second plate 120.

Referring to FIGS. 13, 14 and 15 again, in this embodiment, when the fan wheel 190 is rotated in the second direction controlled by the forward/reverse control unit 181, the rotating blades 192 of the fan wheel 190 enable the air within the accommodating space 140 to generate airflow A1. The swing portion 150 c is to utilize the pivoted portion 150 b as a rotation axis and can be driven by airflow A1 so as to swing toward the inner surface 131 of the ring wall 130. The second opening 161 can be sealed by the swing portion 150 c to prevent the air outside the heat-dissipation fan 100 from exhausting through the vent 114, the passage 160 and the second opening 161 to the accommodating space 140 to avoid a dust obstruction in the vent 114 of the heat-dissipation fan 100.

With reference to FIGS. 13, 14 and 16 again, when the fan wheel 190 is rotated in the first direction controlled by the forward/reverse control unit 181, the first end S1 of the resilient member S is fixed at the spacing rib 150, and the second end S2 is fixed at the active spacing rib 150 a. Therefore, the resilient member S provides an elastic force to enable the swing portion 150 c to utilize the pivoted portion 150 b as a rotation axis and swings toward the fan wheel 190, and the swing portion 150 c is in contact against the pillar P to prevent the swing portion 150 c of the active spacing rib 150 from colliding with the blades 192 of the fan wheel 190 to avoid a destruction of the heat-dissipation fan 100. Referring to FIG. 16, when the swing portion 150 c swings toward the fan wheel 190, the passage 160 communicates with the accommodating space 140. The air inside the accommodating space 140 may be discharged through the second opening 161, the passage 160 and the vent 114 via airflow A2, which may push forward the dust adhered to the accommodating space 140 to be discharged from the heat-dissipation fan 100.

A sixth embodiment of this invention can be referred to FIGS. 17 and 18. The difference between the sixth embodiment and the first embodiment is that a vent is not disposed at the first plate 110. When the spacing rib 150 is disposed at the accommodating space 140, the passage 160 formed between the spacing rib 150 and the ring wall 130 is in communication with an edge 116 of the first plate 110. Referring to FIG. 16, in this embodiment, the passage 160 comprises a vent 164 in communication with the edge 116 of the first plate 110. When the fan wheel 190 is rotated in the first direction controlled by the forward/reverse control unit 181, the air inside the accommodating space 140 may be discharged through the second opening 161, the passage 160 and the vent 164 of the passage 160 via airflow A2, which may push forward the dust adhered to the accommodating space 140 to be discharged from the heat-dissipation fan 100 as well. Accordingly, the cleaning of the heat-dissipation fan 100 and dust exhaustion can be achieved simultaneously.

In each embodiment, when the fan wheel 190 is rotated in the second direction, the air outside the heat-dissipation fan 100 may be exhausted through the first aperture 113 of the first plate 110 and the second aperture 123 of the second plate 120. In the mean time, the air inside the accommodating space 140 may be discharged from the first opening 133 of the ring wall 130 therefore forming a gas circulation for achieving heat dissipation function. Oppositely, when the fan wheel 190 is rotated in the first direction, the air inside the accommodating space 140 may be discharged through the second opening 161, the passage 160 and the vent 114, 124, 164. By discharging the air inside the accommodating space 140, the dust adhered to the accommodating space 140 can be discharged from the heat-dissipation fan 100 as well. Accordingly, the cleaning of the heat-dissipation fan 100 and dust exhaustion can be achieved simultaneously.

While this invention has been particularly illustrated and described in detail with respect to the preferred embodiments thereof, it will be clearly understood by those skilled in the art that it is not limited to the specific features and describes and various modifications and changes in form and details may be made without departing from the spirit and scope of this invention. 

1. A heat-dissipation fan comprising: a first plate having a first top surface, a first bottom surface, a first aperture and a vent; a second plate having a second top surface, a second bottom surface and a second aperture; a ring wall having an inner surface, an outer surface and a first opening, wherein the ring wall is disposed between the first plate and the second plate, and an accommodating space can be defined by the first plate, the second plate and the ring wall; a spacing rib disposed at the accommodating space, wherein a passage is formed between the ring wall and the spacing rib, the spacing rib comprises a first end portion and a second end portion, the second end portion and the ring wall are spaced apart to form a second opening, the passage is in communication with the vent, and the second opening is in communication with the passage and the accommodating space; a stator disposed at the accommodating space; a circuit board having a forward/reverse control unit, wherein the circuit board is electrically connected with the stator; and a fan wheel coupled to the stator, wherein the fan wheel comprises a hub and a plurality of blades, the rotation direction of the fan wheel is controllable by the forward/reverse control unit.
 2. The heat-dissipation fan in accordance with claim 1, wherein the first end portion of the spacing rib is in contact with the inner surface of the ring wall.
 3. The heat-dissipation fan in accordance with claim 2, wherein the first end portion of the spacing rib is formed as one piece with the inner surface.
 4. The heat-dissipation fan in accordance with claim 1, wherein the first end portion of the spacing rib and the inner surface of the ring wall are spaced apart by a first spacing, the second end portion of the spacing rib and the inner surface of the ring wall are spaced apart by a second spacing, and the second spacing is larger than the first spacing.
 5. The heat-dissipation fan in accordance with claim 4, wherein the first spacing has a first width, the second spacing has a second width, and the passage between the spacing rib and the inner surface of the ring wall is tapered from the second width to the first width.
 6. The heat-dissipation fan in accordance with claim 5, wherein the spacing rib can be an arc-shaped plate.
 7. The heat-dissipation fan in accordance with claim 2, wherein the spacing rib is formed as one piece with the first top surface of the first plate.
 8. The heat-dissipation fan in accordance with claim 2, wherein the spacing rib is formed as one piece with the second bottom surface of the second plate.
 9. The heat-dissipation fan in accordance with claim 2 further includes an active spacing rib disposed at the second opening.
 10. The heat-dissipation fan in accordance with claim 9, wherein the active spacing rib comprises a pivoted portion and a swing portion in connection with the pivoted portion, the pivoted portion is pivotally connected with the first top surface of the first plate.
 11. The heat-dissipation fan in accordance with claim 10, wherein the pivoted portion is pivotally connected with the second bottom surface of the second plate.
 12. The heat-dissipation fan in accordance with claim 9 further includes a pillar disposed between the active spacing rib and the blades of the fan wheel.
 13. The heat-dissipation fan in accordance with claim 12, wherein the pillar is formed as one piece with the first top surface of the first plate.
 14. The heat-dissipation fan in accordance with claim 12, wherein the pillar is formed as one piece with the second bottom surface of the second plate.
 15. The heat-dissipation fan in accordance with claim 9 further includes a resilient member, wherein the resilient member comprises a first end and a second end, the first end is fixed at the spacing rib, and the second end is fixed at the active spacing rib.
 16. A heat-dissipation fan comprising: a first plate having a first top surface and a first bottom surface; a second plate having a second top surface and a second bottom surface; a ring wall having an inner surface, an outer surface and a first opening, wherein the ring wall is disposed between the first plate and the second plate, and an accommodating space can be defined by the first plate, the second plate and the ring wall; a spacing rib disposed at the accommodating space, wherein a passage is formed between the ring wall and the spacing rib, the spacing rib comprises a first end portion and a second end portion, the second end portion and the ring wall are spaced apart to form a second opening, the passage comprises a vent in communication with an edge of the first plate, the second opening is in communication with the passage and the accommodating space; a stator disposed at the accommodating space; a circuit board having a forward/reverse control unit, wherein the circuit board is electrically connected with the stator; and a fan wheel coupled to the stator, wherein the fan wheel comprises a hub and a plurality of blades, the rotation direction of the fan wheel is controllable by the forward/reverse control unit.
 17. The heat-dissipation fan in accordance with claim 16, wherein the first end portion of the spacing rib is in contact with the inner surface of the ring wall.
 18. The heat-dissipation fan in accordance with claim 17, wherein the first end portion of the spacing rib is formed as one piece with the inner surface.
 19. The heat-dissipation fan in accordance with claim 16, wherein the first end portion of the spacing rib and the inner surface of the ring wall are spaced apart by a first spacing, the second end portion of the spacing rib and the inner surface of the ring wall are spaced apart by a second spacing, and the second spacing is larger than the first spacing.
 20. The heat-dissipation fan in accordance with claim 19, wherein the first spacing has a first width, the second spacing has a second width, and the passage between the spacing rib and the inner surface of the ring wall is tapered from the second width to the first width.
 21. The heat-dissipation fan in accordance with claim 17 further includes an active spacing rib disposed at the second opening, and the active spacing rib comprises a pivoted portion and a swing portion in connection with the pivoted portion.
 22. A heat-dissipation fan comprising: a plate having a top surface, a bottom surface and a vent; a ring wall having an inner surface, an outer surface and a first opening, wherein the ring wall is disposed at the plate, and an accommodating space can be defined by the plate and the ring wall; a spacing rib disposed at the accommodating space, wherein a passage is formed between the ring wall and the spacing rib, the spacing rib comprises a first end portion and a second end portion, the second end portion and the ring wall are spaced apart to form a second opening, the passage is in communication with the vent, the second opening is in communication with the passage and the accommodating space; a stator disposed at the accommodating space; a circuit board electrically connected with the stator; and a fan wheel coupled to the stator, wherein the fan wheel comprises a hub and a plurality of blades, the rotation direction of the fan wheel is controllable by the circuit board.
 23. The heat-dissipation fan in accordance with claim 22, wherein the first end portion of the spacing rib is in contact with the inner surface of the ring wall.
 24. The heat-dissipation fan in accordance with claim 23, wherein the first end portion of the spacing rib is formed as one piece with the inner surface.
 25. The heat-dissipation fan in accordance with claim 22, wherein the first end portion of the spacing rib and the inner surface of the ring wall are spaced apart by a first spacing, the second end portion of the spacing rib and the inner surface of the ring wall are spaced apart by a second spacing, and the second spacing is larger than the first spacing.
 26. The heat-dissipation fan in accordance with claim 25, wherein the first spacing has a first width, the second spacing has a second width, and the passage between the spacing rib and the inner surface of the ring wall is tapered from the second width to the first width.
 27. The heat-dissipation fan in accordance with claim 26, wherein the spacing rib can be an arc-shaped plate.
 28. The heat-dissipation fan in accordance with claim 23, wherein the spacing rib is formed as one piece with the first top surface of the first plate.
 29. The heat-dissipation fan in accordance with claim 23, wherein the spacing rib is formed as one piece with the second bottom surface of the second plate. 